1. Technical Field
The present disclosure relates to audio processing apparatuses, audio processing methods, and audio processing programs that acquire audio signals indicating sounds surrounding users and carry out predetermined processing on the acquired audio signals.
2. Description of the Related Art
One of the basic functions of hearing aids is to make the voice of a conversing party more audible. To achieve this function, adaptive directional sound pickup processing, noise suppressing processing, sound source separating processing, and so on are employed as techniques for enhancing the voice of the conversing party. Through these techniques, sounds other than the voice of the conversing party can be suppressed.
Portable music players, portable radios, or the like are not equipped with mechanisms for taking the surrounding sounds thereinto and merely play the content stored in the devices or output the received broadcast content.
Some headphones are provided with mechanisms for taking the surrounding sounds thereinto. Such headphones generate signals for canceling the surrounding sounds through internal processing and output the generated signals mixed with the reproduced sounds to thus suppress the surrounding sounds. Through this technique, the user can obtain the desired reproduced sounds while noise surrounding the user of the electronic apparatuses for reproduction is being blocked.
For example, a hearing aid apparatus (hearing aid) disclosed in Japanese Unexamined Patent Application Publication No. 2005-64744 continuously writes external sounds collected by a microphone into a ring buffer. This hearing aid apparatus reads out, among the external sound data stored in the ring buffer, external sound data corresponding to a prescribed period of time and analyzes the read-out external sound data to determine the presence of a voice. If the result of an immediately preceding determination indicates that no voice is present, the hearing aid apparatus reads out the external sound data that has just been written into the ring buffer, amplifies the read-out external sound data at an amplification factor for environmental sounds, and outputs the result through a speaker. If the result of an immediately preceding determination indicates that no voice is present but the result of a current determination indicates that a voice is present, the hearing aid apparatus reads out, from the ring buffer, the external sound data corresponding to the period in which it has been determined that a voice is present, amplifies the read-out external sound data at an amplification factor for a voice while time-compressing the data, and outputs the result through the speaker.
A speech rate conversion apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2005-148434 separates an input audio signal into a voice segment and a no-sound-and-no-voice segment and carries out signal processing of temporally extending the voice segment into the no-sound-and-no-voice segment to thus output a signal that has its rate of speech converted. The speech rate conversion apparatus detects, from the input audio signal, a forecast-sound signal in a time signal formed of the forecast-sound signal and a correct-alarm-sound signal. When the speech rate conversion apparatus detects the forecast-sound signal, the speech rate conversion apparatus deletes the time signal from the voice segment that has been subjected to the signal processing. In addition, when the speech rate conversion apparatus detects the forecast-sound signal, the speech rate conversion apparatus newly generates a time signal formed of the forecast-sound signal and the correct-alarm-sound signal. The speech rate conversion apparatus then combines the newly generated time signal with an output signal such that the output timing of the correct-alarm sound in the stated time signal coincides with an output timing in a case in which the correct-alarm sound in the time signal of the input audio signal is to be output.
A binaural hearing aid system disclosed in Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2009-528802 includes a first microphone system for the provision of a first input signal, the first microphone system is adapted to be placed in or at a first ear of a user; and a second microphone system for the provision of a second input signal, the second microphone system is adapted to be placed in or at a second ear of the user. The binaural hearing aid system automatically switches between an omnidirectional (OMNI) microphone mode and a directional (DIR) microphone mode.
The above-described conventional techniques require further improvements.